Disruption claims remain one of the most complex and contested areas in construction dispute resolution. While complaints of disruption and associated cost overruns are common, proving them continues to be a significant challenge.

The 2025 edition of The Analysis and Valuation of Disruption offers an updated framework for understanding, evidencing, and quantifying disruption in construction projects. It reflects the latest thinking, quantitative insights drawn from legal precedents, and industry practices, with a strong emphasis on evidentiary rigour and methodological integrity.

Key themes include:

• Understanding Disruption: Disruption is defined as a disturbance to a contractor’s planned working methods, resulting in reduced efficiency. Unlike delay, which affects time, disruption impacts productivity and is often harder to detect and document in real time.
• The Burden of Proof: Successful disruption claims require a clear demonstration of entitlement, causation, and quantifiable loss. This includes identifying the disruptive event, proving it was a compensable risk under the contract, and linking it to measurable impacts.
• The Role of Documentation: The paper underscores the critical importance of contemporaneous records, daily logs, schedules, RFIs, and cost data, in substantiating claims. Without these, even well-founded claims may fail.
• Quantifying Loss: A range of methodologies are explored, from the widely accepted Measured Mile and Earned Value Analysis to more contentious approaches like Total Cost and Productivity Factors. The paper provides a comparative analysis of tribunal acceptance rates across 316 cases, offering practical guidance on which methods are most likely to succeed.
• Legal and Contractual Considerations: The paper examines how disruption is treated under standard forms of contract, the implications of time-bar clauses, and the evidentiary standards required by courts and tribunals.
• Expert Evidence: Expert testimony remains essential in bridging the gap between disruption events and financial loss. However, it must be grounded in robust data and sound methodology.
• Best Practice Recommendations: The paper advocates for proactive disruption recognition, integrated project controls, and structured reporting to improve claim success rates and project outcomes.

This updated edition is an essential resource for contractors, legal professionals, and construction consultants seeking to navigate the complexities of disruption claims with confidence and clarity.

Complaints of ‘disruption’ and additional costs are routinely made during the course of a construction project, yet they remain notoriously difficult to prove.

Derek Nelson, Partner